Mexico Border Wall Won’t Stop Cross-border Power Push

Mexico and its U.S. neighbors are planning expanded electrical trade even as President Trump continues pushing to build a border wall. New transmission links and greater use of existing connections could ease the integration of renewable energy by both countries.

Relations between the United States and Mexico are strained at the national level, with President Donald Trump pushing his promised border control wall and demanding a U.S.-favored rewrite of the North American Free Trade Agreement (NAFTA). But Mexico and the southwestern states have continued working towards an international agenda for electricity, and regional players are talking up a first set of projects due to be completed before Trump’s term is up — projects that put the region on a path to a far more electrically-porous border.

These projects include a trio of new crossborder links between California, Arizona and Mexico to be completed in the next three years. They also include grid studies, revised market rules, and new power lines within Mexico that could rapidly expand flows over all of the U.S.-Mexico interties. "The proposition right now is fairly small because the interconnections are small. But that’s going to change,” says Carl Zichella, director for Western transmission at the Natural Resources Defense Council.

Transmission experts such as Zichella trace today's momentum back to energy reforms enshrined in Mexico’s constitution in 2014. Those reforms opened up Mexico's state-dominated energy sector, providing access to private and foreign investment for energy infrastructure and unleashing rapid development of some of North America’s best renewable energy resources.

A more porous border will ease the challenge of backing up that variable renewable power, which is growing on both sides of the border. Duncan Wood, director of the Mexico Institute at the Wilson Center in Washington, D.C. highlights the opportunity to trade wind power between Mexico’s San Fernando Valley, where wind blows hard during the day, and the West Texas wind power farms that run strongest overnight. "If you can link those you might be able to meet peak demand in both the U.S. and Mexico and avoid having natural gas backup,” says Wood.

Mexico's power grids presently intersect with their U.S. counterparts at 11 points, but more than half of those links can exchange just 100 megawatts (MW) or less and almost half operate only during grid emergencies [see map below]. There are also a few dedicated lines serving individual power plants, such as one that links a natural gas-fired generator in Mission, Texas to Mexican consumers.

Image: Mexico Ministry of Energy (SENER)
Many US-Mexico electric interties operate at relatively low voltage (ie low tensión) and are used infrequently – some only during emergencies.

Today's cross-border construction plans, in contrast, go well beyond spur lines and emergency links. The focus is on robust connections between Mexico and the giant synchronized zone operated by the Western Electricity Coordinating Council (WECC) which shares alternating current amongst most of the western U.S. and Canada as well as the northernmost portion of Baja California in Mexico.

"Everything has just gone lightning speed. The political will is there,” says Antonio Ortega, who manages governmental affairs and communications for the Imperial Irrigation District (IID), which operates the grid in California’s Imperial Valley. IID and CENACE signed a memorandum in May to study exchanging up to 600 MW, and Ortega says they now have plans mapped out for a pair of interties to be completed in 2019 and 2020.

Ortega says IID has secured a substation site for one link, and is fielding calls from local geothermal developers and solar developers eager to access the Mexican market. "If all 600 MW of renewable energy development is built it would be an economic boon to the region,” he says.

CENACE and the California Independent System Operator (CAISO), which controls the state’s major grids, are looking to get more out of the existing 800-MW link between the San Diego region and Baja California. Roberto Bayetti, a CAISO working closely with Mexico’s power sector, says the link is used sporadically such as when an outage leaves one side or the other short temporarily. Now they are talking about using the link to integrate renewable energy.

Bayetti says 675-MW of renewable generation under development in Baja California could help the San Diego region, which has relied heavily on imports since the region's San Onofre nuclear power station closed down in 2013. "That would alleviate some of that congestion for us and provide a big opportunity for both sides to reduce carbon,” says Bayetti.

Greater opportunity for both IID and CAISO will open up thanks to internal transmission projects in Mexico. One that is in advanced planning is a high-voltage direct current (HVDC) line that will, for the first time, link northern Baja (and thus California's grids) to Mexico’s main grid. "There is huge potential. Now we’re not talking about 800 MWs. We’re talking about thousands of MWs that could be transferred,” says Bayetti.

CENACE’s grid plan sees future developments pushing east to Texas, including additional cross-border HVDC links at Ciudad Juarez and Reynosa and a possible East-West HVDC line tracking south of the border from Baja to close to the Gulf of Mexico. Those projects would expand exchanges with the Texas grid – a stand-alone AC zone managed by the Electric Reliability Council of Texas (ERCOT).

Power system experts are optimistic that the U.S.-Mexico agenda will survive the Trump era, since the action is between regional entities. "Things are just marching along underneath any type of political discussion at the higher elevations,” says Paul Roberti, executive director for power and utilities with EY México, a branch of global accountancy and consulting firm Ernst and Young.

As for President Trump’s border wall? Eight prototypes have been erected near the Otay Mesa border crossing between San Diego and Tijuana [see photo at top]. But the wall itself may be stillborn since, as Reuters noted this week, "Congress has so far shown little interest in appropriating the estimated $21.6 billion it would cost to build the wall.”